A redesigned Profile Account card: a clear Sign in / Create account switch, the username field only when creating an account, and a sign out you can't miss. Three iterations in — open it and try all three states.

The full reset flow behind the sign-in card's "Forgot password?" link: request a link, check your email, set a new password — plus the expired-link screen and an honest look at the plain system email that actually arrives. Three iterations in — walk it end to end, including an hour later.